1. Field of the Invention
The invention relates in general to transportation apparatus, and more specifically to moving stairways or escalators, for transporting people between spaced landings.
2. Description of the Prior Art
U.S. Pat. No. 2,981,397, discloses several embodiments of escalators directed to reducing the possibility of objects entering and being caught between relatively movable portions of the escalator. For example, as disclosed in this patent, the outer cleats of the step tread part may be constructed of a resilient material which has a lower coefficient of friction than the remaining cleats.
U.S. Pat. No. 3,986,595, discloses disposing a sensor element such that contact therewith actuates a displacement element to narrow the running gap or clearance between the step of an escalator and the adjacent skirt board.
U.S. Pat. No. 4,004,676, which is assigned to the same assignee as the present application, discloses constructing the steps of an escalator such that they have projecting portions which define fillets between the riser part and the adjacent skirt boards.
U.S. Pat. No. 4,236,623, discloses placing plastic strips along each lateral edge of the tread part. The strips include a plurality of ribs which extend into the grooves of the tread part. The strips are shaped to form a ramp-like face which angles upwardly from the horizontal surface of the tread part.